1. Field of the Invention
The present invention relates to an optical disc player for playing an optical disc, and in particular to a portable DVD player having a display that may be used outdoors also.
2. Description of the Related Art
In a related art, optical disc players for playing video or voice recorded on an optical disc such as a CD and a DVD have been in commercial use. In practical use are portable DVD players equipped with a small display suitable for outdoor applications. A general portable DVD player includes a switch for toggling between an external signal and an internal signal. The external signal is related to video and voice of an externally input television broadcast. The internal signal is related to video and voice recorded on a DVD played back in a disc player. The user operates the switch to selectively output video or voice corresponding to the external signal or the internal signal.
As the switch operated by the user to toggle between an external signal and an internal signal, a lock slide switch that maintains the post-operation state is mounted on a side of the main unit case of a general portable DVD player. When the main unit is powered, the portable DVD player displays, for a certain time, via OSD, on the display, which of the external or internal signal is selected by the switch. As described in JP-UM-A-3050205 for example, a synchronization detection circuit for detecting the synchronization of a video signal output to an output terminal and an OSD image generation circuit for generating a video signal corresponding to an OSD image overlaid on the image of a video signal output to an output terminal are provided before the output terminal. When the main unit is powered, which of the external or internal signal is selected is displayed on the display via OSD for a certain time. Main reasons for this configuration are described below.
When the user operates the portable DVD player without an external input signal coupled thereto, in case the external signal is selected by the switch, video or voice recorded on a DVD set in the main unit, if any. The external signal is not coupled, so that the video or voice corresponding to the external signal selected by the switch is not output. In other words, the portable DVD player does not output video or voice. As mentioned above, the switch for toggling between an external signal and an internal signal is a slide switch mounted on the side face of the main unit case. The user could assume a unit fault without checking the switch state. In order to avoid the user's misunderstanding, an OSD image is used to let the user recognize the switch state.